Multi-duct air conditioning system

ABSTRACT

A multi-duct air conditioning system for air conditioning a number of rooms and/or room zones includes: at least one air inlet device to each room to be air conditioned or to each room zone; at least two supply air fans; a control unit for controlling the supply air fans; and at least two supply air ducts. At least one supply air fan is situated in each of the supply air ducts.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-duct air conditioning system, and to a method for operating this system.

2. Description of the Related Art

A dual-duct system is known from published German patent document DE 10 2008 010 656 B3, which includes a supply air fan. This supply air fan generally transports recirculating air and/or fresh air into the dual-duct system. A heating register is provided downstream from the supply air fan.

Downstream from the heating register, the supply air duct is divided into two supply air ducts, into which flap devices in the form of control flaps are introduced. With the aid of these, the air volumes for the particular supply air ducts are set. Branching ducts lead from the supply air ducts to the rooms or room zones to be air conditioned. Additional flaps are provided upstream from the rooms or room zones to be air conditioned for controlling the air volume from the particular supply air duct for the room to be air conditioned or the room zone to be air conditioned. An intake duct, which may be connected to a fresh air duct and a recirculating air duct, is provided upstream from the supply air fan.

The known dual-duct system has the disadvantage that only one supply air fan is provided. In this way, the entire system is shut down in the event of failure of this supply air fan since it is no longer possible to supply fresh air and/or recirculating air to the supply air ducts. Moreover, pressure losses may occur as a result of the flaps being introduced into the supply air ducts after the division into the two supply air ducts. In this way energy is lost, which impairs the efficiency of the dual-duct air conditioning system.

In the known dual-duct air conditioning system, it is possible to supply fresh air as well as recirculating air to the supply air fan. The recirculating air portion is dependent on the air quality of the recirculating air and the air quality in the room to be air conditioned or the room zone to be air conditioned, the energy content of the recirculating air, and the energy demand in the rooms or room zones to be air conditioned. However, the conditions and requirements for the rooms or room zones to be air conditioned may be quite different, so that a varying recirculating air demand may result relative to the rooms or room zones to be air conditioned. The known dual-duct air conditioning system is not able to satisfy this varying recirculating air demand since the dual-duct air conditioning system is not designed flexibly enough for this purpose, in particular to be able to cover the varying energy demand in conjunction with the varying air quality requirements relative to the supply air ducts.

The following situation may exist, for example: The known dual-duct air conditioning system air conditions multiple rooms. During winter operation, there is demand in all rooms for heating, so that warm air having a certain temperature is supplied in a supply air duct. Corresponding to the energy demand of the rooms, the air volume from only one supply air duct is needed. Supply air from the other duct is not needed. The air quality decreases in a room, so that the demand for fresh air increases in this room. The consequence of this in the known dual-duct air conditioning system is that the recirculating air portion considerably decreases, and the fresh air portion increases. The fresh air portion depends on the target specifications of the room having the worst air quality. As a result, all rooms are supplied with a higher fresh air portion than necessary. This results in considerable energy losses.

It is therefore the object of the present invention to refine a multi-duct air conditioning system in such a way that the described disadvantages are avoided, and a more purposeful regulation of the multi-duct air conditioning system is facilitated.

BRIEF SUMMARY OF THE INVENTION

The present invention is based on the finding that providing a supply air fan in at least two supply air ducts of the multi-duct air conditioning system of the type in question not only increases the reliability against failure, but also allows energy to be saved, since greater flexibility in the control and regulation results for the supply of supply air having different parameters or air qualities.

According to the present invention, at least two supply air fans are thus provided, at least one supply air fan being situated in each case in different supply air ducts. In this way, a higher reliability against failure of the multi-duct air conditioning system may be ensured, and energy savings may be achieved, in a simple manner.

The flexibility and effectiveness of the regulation may preferably be further increased when one supply air fan is introduced into each supply air duct. Via the supply air fan, it is possible not only to individually control the supply air volume per supply air duct, but additionally this provides the greatest reliability against failure.

According to one specific embodiment of the present invention, an intake duct having a connected recirculating air duct and/or fresh air duct is provided. The supply air duct is referred to as an intake duct upstream from the supply air fan. It is used to supply recirculating air and/or fresh air to the supply air fans. The supply air for the rooms or room zones to be air conditioned may thus be formed of recirculating air and/or fresh air.

In particular, the control unit controls the rotational speeds of all supply air fans, and thus the air volume to be transported in the particular supply air ducts.

Preferably at least one flap assigned to each supply air duct is provided in each case, the flap set by the control unit establishing the proportionate supply air from the particular supply air ducts to the room to be air conditioned or to the room zone.

Each supply air fan may be connected to an intake duct, which is connected to a recirculating air duct and/or a fresh air duct.

According to one specific embodiment of the present invention, preferably one or multiple of the following features a) through c) is/are met:

-   a) at least one fresh air flap is introduced into the fresh air     duct, in particular the control unit regulating the fresh air flap; -   b) a recirculating air flap is introduced into the recirculating air     duct, in particular the control unit regulating the recirculating     air flap to establish the recirculating air portion of the supply     air; -   c) an outgoing air duct is provided, and an outgoing air flap is     introduced into the outgoing air duct, in particular the control     unit regulating the outgoing air flap to establish the outgoing air     portion of the exhaust air.

The control unit may cooperate with climate sensors introduced into the rooms, room zones and/or supply air [ducts] and/or exhaust air ducts, namely sensors for temperature, moisture, air quality, density, and pressure.

The portion of the recirculating air and/or of the fresh air in the supply air to the supply air fan of the particular supply air duct is preferably established by the control unit as a function of at least one parameter from the group of the following parameters: temperature, moisture, air quality, density, and pressure. The climate sensors may be situated in the rooms to be air conditioned or the room zones, in the exhaust air duct, in the outgoing air duct, in the fresh air duct, in the recirculating air duct and/or in the supply air duct, i.e., overall in compartments. The climate sensors may detect the following measured values/actual values: temperature, moisture, air quality, density, and pressure.

These are compared to the setpoint values stored in the control unit and evaluated, whereby control parameters are derived which are assigned control signals for the actuators of the air conditioning system, and control signals for the supply air fans.

In particular, the control unit regulates the rotational speeds of the supply air fans as a function of the requirements of supply air to the particular rooms or room zones in accordance with the supply air portions, which are based on parameters of the climate sensors.

Preferably at least one supply air duct includes at least one component from the following group of air preparation units: cooling registers, heating registers, humidifiers, dehumidifiers, air filters, aromatizers, ionizers, etc.

The flexibility of the system may also be increased by connecting the supply air ducts to each other via a bypass duct, a bypass flap being introduced into the bypass duct. For example, in the event of the failure of one supply air fan, it is possible to supply supply air from the further supply air duct connected via the bypass duct to ensure the reliability against failure.

The bypass flap may cooperate with the control unit for this purpose.

According to one further aspect of the present invention, the present invention relates to a method for operating a multi-duct system. The following method steps are provided:

-   a) using the climate sensors, such as a pressure sensor, a     temperature sensor, a moisture sensor, a sensor for the air quality     and the like, the actual condition in the particular compartments     such as ducts, rooms and room zones is detected and compared to the     setpoint values stored in the control unit and evaluated, whereby     control parameters are derived; -   b) as a function of the control parameters, the control unit     establishes the rotational speeds of the supply air fans and the     flap positions of the flaps assigned in each case to the supply air     ducts, whereby the proportionate assignment of the supply air volume     from the particular supply air ducts to the room to be air     conditioned or the room zones results.

In particular, the following method step may be carried out:

-   c) the supply air is prepared as a function of the control     parameters.

Preferably the following method step is carried out:

-   d) the distribution of the air volume of the supply air to the rooms     to be air conditioned and/or to the room zones takes place as a     function of the control parameters.

According to one further aspect, the following method step is carried out:

-   e) the exhaust air motor, the exhaust air flap and/or the outgoing     air flap and overflow flaps are regulated as a function of the     control parameters.

Preferably the following method step is carried out to take the energy content of the exhaust air into consideration:

-   f) the recirculating air portion and/or fresh air portion is/are set     as a function of the control parameters.

In particular, the preparation of the air is carried out according to the physical characteristic values as a function of the control parameters.

Additional advantages, features and application options of the present invention are derived from the following description in conjunction with the exemplary embodiments shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a dual-duct air conditioning system according to the present invention.

FIG. 2 shows a schematic diagram of the control unit including the connected actuators and climate sensors.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a block diagram of a dual-duct air conditioning system 2 according to the present invention. Dual-duct air conditioning system 2 includes two supply air ducts 4, 6. A supply air fan 8, 10 and a heating register 12, 14 provided downstream from the particular supply air fan 8, 10 are introduced into each supply air duct 4, 6. A temperature sensor 16, 18 is provided downstream from heating register 12, 14 in each case. Downstream from the temperature sensor 16, 18, a bypass duct 20 connecting two supply air ducts 4, 6 is provided. A bypass flap 22, which is actuated by a bypass flap motor 22 a, is introduced into bypass duct 20.

Each supply air duct 4, 6 is connected to a fresh air duct 24, 26 and a recirculating air duct 28, 30. Upstream from supply air fan 8, 10, supply air duct 4, 6 is also referred to as the intake duct.

Downstream from temperature sensor 16 and bypass duct 20 in first supply air duct 4, initially a cooling register 32, then a heating register 34, and finally a humidifier 36 are provided downstream. Finally, a temperature sensor 38, a moisture sensor 40, and a pressure sensor 42 are also introduced into first supply air duct 4 downstream from humidifier 36. First supply air duct 4 is connectable in each case to rooms 44, 46 and 48. A branching duct 50 is provided for this purpose in each case, which is connected to an air inlet 52 for the particular room 44, 46, 48. Branching duct 50 is part of first supply air duct 4. A flap 54, which is actuated via a motor 56, is introduced into this branching duct 50.

Second supply air duct 6 is composed in the same manner as first supply air duct 4. Downstream from temperature sensor 18 and bypass duct 20, a cooling register 58, a heating register 60, and a humidifier 62 are provided downstream. A temperature sensor 64, a moisture sensor 66, and a pressure sensor 68 follow humidifier 62.

A second branching duct 70, which is connected to air inlet 52 of the particular rooms 44, 46, 48, extends from second supply air duct 6. A flap 72, which is actuated by a motor 74, is introduced into second branching duct 70.

A temperature sensor 76, a moisture sensor 78, and an air quality sensor 80 are provided in each case in rooms 44, 46, 48. The individual sensors are used to detect and regulate the temperature, moisture and air quality in rooms 44, 46, 48. A corresponding setpoint value is predefined for the particular room in the control loop. Cooling register 32, 58, heating register 34, 60, and humidifier 36, 62 are only activated in the particular supply air duct 20, 22 if, based on demand, the temperature for cooling or heating rooms 44, 46, 48 to be air conditioned or the degree for humidification is not sufficient in at least one of supply air ducts 4, 6. In general, air inlet 52 in rooms 44, 46, 48 to be air conditioned is only connected to one supply air duct 4 or 6. In this way, the air is no longer mixed, but withdrawn from either first supply air duct 4 or second supply air duct 6.

Flaps 54 and 72 are used to set the required air volume needed in each case in the rooms or room zones. The supply air volume for the particular rooms 44, 46, 48 to be air conditioned varies as a function of the measured values of the sensors detected in the control unit and their evaluation, and the resulting control parameters.

The pressure in supply air ducts 4, 6 is regulated in rooms 44, 46, 48 to be air conditioned via supply air fans 8, 10 as a function of the required air volume.

Cooling registers 32, 58, heating registers 34, 60, and humidifiers 36, 62 are only activated when the temperature and/or the density values and/or the moisture levels in the particular supply air ducts 20, 22 do not meet the requirements.

Cooling registers 32, 58 and heating registers 12, 14, 34 and 60 are settable via a predetermined temperature range.

Flaps 54 and 72 are designed in such a way that, depending on the requirement, it is also possible to connect only one of supply air ducts 4, 6 to air inlet 52 in rooms 44, 46, 48 to be air conditioned. Flaps 54 and 72 are additionally used to control the air volume from the particular supply air duct 4, 6 independently of each other.

The exhaust air is transported out of rooms 44, 46, 48 via an exhaust air duct 82. For this purpose, an exhaust air fan 84 is introduced into exhaust air duct 82. A recirculating air duct 86 branches off exhaust air duct 82, branching into recirculating air ducts 28 and 30. The branching of recirculating air duct 86 off exhaust air duct 82 is provided downstream from outgoing air duct 88.

An outgoing air flap 90, which is actuated by an outgoing air flap motor 92, is introduced into outgoing air duct 88. Moreover, a recirculating air flap 94, which is actuated by recirculating air flap motor 96, is introduced into recirculating air duct 28. In similar fashion, a recirculating air flap 98, which is actuated by a recirculating air flap motor 100, is introduced into recirculating air duct 30.

A fresh air flap 102 is introduced into fresh air duct 24, and a fresh air flap 104 is introduced into fresh air duct 26. Fresh air flap 102 is actuated by a fresh air flap motor 106, and fresh air flap 104 is actuated by a fresh air flap motor 108.

FIG. 2 shows a representative schematic diagram of a control unit 110 of dual-duct air conditioning system 2 from FIG. 1. Control unit 110 is connected via signal lines 112 to the climate sensors, i.e., to temperature sensor 16, temperature sensor 18, temperature sensor 38, moisture sensor 40, pressure sensor 42, temperature sensor 64, moisture sensor 66, pressure sensor 68, temperature sensor 76, moisture sensor 78, and air quality sensor 80.

Moreover, control unit 110 is connected via signal lines 114 to the motors of the individual flaps, i.e., to bypass flap motor 22 a, the motor for the flap in first branching duct 56, the motor for the flap in second branching duct 74, outgoing air flap motor 92, recirculating air flap motor 96, recirculating air flap motor 100, fresh air flap motor 108, and fresh air flap motor 104.

Control unit 110 is connected via signal lines 116 to the fans and the air preparation units, i.e., to supply air fan 8, supply air fan 10, exhaust air fan 84, heating register 12, heating register 14, cooling register 32, heating register 34, humidifier 36, cooling register 58, humidifier 62, and heating register 60, and optional air quality improvement units, which are not shown in the drawing, such as aromatizers, ionizers, etc.

Control unit 110 regulates the dual-duct air conditioning system in the following method steps.

-   a) Using climate sensors 16, 18, 38, 40, 42, 64, 66, 68, 76, 78, 80,     the actual condition in the particular assigned compartments—i.e.,     ducts, rooms, room zones, etc.—is detected and compared to the     setpoint values stored in control unit 110 and evaluated, whereby     assigned control parameters are derived. -   b) The fresh air portion and/or recirculating air portion is set as     a function of the control parameters via the positions of     recirculating air flap 94, 98 and of fresh air flap 102 and 104 and,     if necessary, also of outgoing air flap 90. For this purpose, motors     92, 96, 100, 106, 108 receive corresponding actuating signals from     control unit 110. -   c) The supply air is prepared as a function of the control     parameters. Depending on the requirement, cooling is carried out by     cooling registers 32, 58, heating by heating registers 12, 14, 34,     60, humidification by humidifier 36, 62, and dehumidification by the     cooperation of cooling registers 32, 58 and heating registers 34,     60. -   d) The rotational speeds of supply air fans 8, 10 and the flap     positions of flaps 54, 72 assigned in each case to supply air ducts     4, 6 are established by control unit 110 as a function of the     control parameters, whereby the proportionate assignment of the     supply air volume from the particular supply air ducts 4, 6 is     derived. For this purpose, motors 56, 74 receive corresponding     actuating signals from control unit 110. -   e) Exhaust air motor 84 and outgoing air flap 92 are regulated as a     function of the control parameters. Downstream from rooms 44, 46,     48, exhaust air flaps are introduced into exhaust air duct 82, which     for the sake of clarity are not shown in FIGS. 1 and 2. These are     also regulated as a function of the control parameters. Instead of     an exhaust air duct 82, this duct may be partially or completely     replaced by an overflow opening with or without a flap. The flap may     also be regulated by control unit 110, in particular as a function     of the control parameters.

Air conditioning system 2 according to the present invention may maintain a variable temperature in each supply air duct 4, 6, the minimum supply air temperature being settable to a minimum setpoint value and/or the maximum supply air temperature being settable to a maximum setpoint value.

First supply air duct 4 and second supply air duct 6 may have differently large cross sections for differently large supply air volumes and differently powerful cooling and/or heating registers.

Application example during the winter, i.e., there is a high demand for heating:

Demand for heating exists in all rooms. The supply air is thus primarily a transport medium for thermal energy. At low atmospheric loads, a high recirculating air portion may be used. For example, multiple occupied office rooms and one empty conference room are involved. All rooms are supplied by the first supply air duct, which supplies warm supply air. The flaps are set accordingly to ensure the great portion of recirculating air. The high demand for heating results in a high air volume to be transported, and thus high rotational speeds of the supply air fan in the first supply air duct. Due to the great portion of recirculating air, the energy content of the exhaust air may be used, and the additional heating power may be reduced.

The conference room now fills; the conference room is heated by the persons, resulting in a reduced heating requirement in the conference room. Additionally, the air quality in the conference room decreases, whereby the requirement of fresh air increases. To achieve this, and to satisfy the unchanged requirements in the office rooms, the conference room is now supplied by the second supply air duct, which conducts cooler supply air than the first supply air duct and a higher fresh air portion. A more individual adaptation to the requirements in the particular rooms is possible in this way, and more considerable energy savings may be achieved, despite an additional supply air fan.

A dual-duct air conditioning system was described based on the figures. Of course the present invention also applies to all multi-duct systems.

In addition to the described air preparation units, it is also possible for additional air preparation units to be introduced into the multi-duct air conditioning system, such as aromatizers, ionizers, etc.

In addition, multiple exhaust air fans may also be provided in one exhaust air duct and/or in multiple exhaust air ducts.

LIST OF REFERENCE NUMERALS

-   2 dual-duct air conditioning system -   4 supply air duct—top -   6 supply air duct—bottom -   8 supply air fan—top -   10 supply air fan—bottom -   12 heating register—top -   14 heating register—bottom -   16 temperature sensor—top -   18 temperature sensor—bottom -   20 bypass duct -   22 bypass flap -   22 a bypass flap motor -   24 fresh air duct—top -   26 fresh air duct—bottom -   28 recirculating air duct for supply air duct 4 -   30 recirculating air duct for supply air duct 6 -   32 cooling register -   34 heating register -   36 humidifier -   38 temperature sensor -   40 moisture sensor -   42 pressure sensor -   44 room to be air conditioned -   46 room to be air conditioned -   48 room to be air conditioned -   50 branching duct off first supply air duct -   52 air inlet in the room to be air conditioned, air inlet -   device -   54 flap in the first branching duct -   56 motor for the flap in the first branching duct -   58 cooling register -   60 heating register -   62 humidifier -   64 temperature sensor -   66 moisture sensor -   68 pressure sensor -   70 second branching duct -   72 flap in the second branching duct -   74 motor for the flap in the second branching duct -   76 temperature sensor -   78 moisture sensor -   80 air quality sensor -   82 exhaust air duct -   84 exhaust air fan -   86 recirculating air duct -   88 outgoing air duct -   90 outgoing air flap -   92 outgoing air flap motor -   94 recirculating air flap -   96 recirculating air flap motor -   98 recirculating air flap -   100 recirculating air flap motor -   102 fresh air flap -   104 fresh air flap motor -   106 fresh air flap -   108 fresh air flap motor -   110 control unit -   112 signal lines -   114 signal lines -   116 signal lines 

1-15. (canceled)
 16. A multi-duct air conditioning system for air conditioning multiple room zones, comprising: at least one air inlet device to each room zone to be air conditioned; at least two supply air fans; a control unit; and at least two supply air ducts, wherein at least one supply air fan is situated in each of the at least two supply air ducts.
 17. The multi-duct air conditioning system as recited in claim 16, wherein at least one of (i) a recirculating air duct for supplying recirculating air to the supply air fans, and (ii) a fresh air duct for supplying fresh air to the supply air fans is provided.
 18. The multi-duct air conditioning system as recited in claim 17, wherein the control unit controls the rotational speeds of all supply air fans, and thereby controls the air volume to be transported in each supply air duct.
 19. The multi-duct air conditioning system as recited in claim 18, wherein at least one flap is assigned to each supply air duct, and wherein each flap is set by the control unit to establish the proportionate supply air from each supply air duct to the respective room zone to be air conditioned.
 20. The multi-duct air conditioning system as recited in claim 19, wherein each supply air fan is connected to an intake duct, and wherein the intake duct is connected to at least one of the recirculating air duct and the fresh air duct.
 21. The multi-duct air conditioning system as recited in claim 20, wherein at least one of: a) at least one fresh air flap is introduced into the fresh air duct, and the control unit regulates the fresh air flap; b) a recirculating air flap is introduced into the recirculating air duct, and the control unit regulates the recirculating air flap to establish the recirculating air portion of the supply air; and c) an outgoing air duct is provided, and an outgoing air flap is introduced into the outgoing air duct, and the control unit regulates the outgoing air flap to establish the outgoing air portion of the exhaust air.
 22. The multi-duct air conditioning system as recited in claim 19, wherein the control unit cooperates with climate sensors located in at least one of the room zones, the supply air ducts, and exhaust air ducts.
 23. The multi-duct air conditioning system as recited in claim 22, wherein the portion of at least one of the recirculating air and fresh air in the supply air to the supply air fan of the respective supply air duct is controlled by the control unit as a function of at least one of temperature, moisture, air quality, density, and pressure.
 24. The multi-duct air conditioning system as recited in claim 22, wherein the control unit regulates the rotational speeds of the supply air fans as a function of the requirements of supply air to the respective room zones in accordance with the supply air portions which are based on parameters of the climate sensors.
 25. The multi-duct air conditioning system as recited in claim 18, wherein the supply air ducts are connectable to each other via a bypass duct having a bypass flap.
 26. The multi-duct air conditioning system as recited in claim 25, wherein the bypass flap is controlled by the control unit.
 27. A method for operating a multi-duct air conditioning system for air conditioning multiple room zones, the multi-duct air conditioning system including at least one air inlet device to each room zone to be air conditioned, at least two supply air fans, a control unit, and at least two supply air ducts each having a flap, wherein at least one supply air fan is situated in each of the at least two supply air ducts, the method comprising: detecting, using climate sensors, actual condition in each room zone; comparing the detected actual condition in each room zone to a setpoint value stored in the control unit to determine control parameters; and controlling, by the control unit, the rotational speeds of the supply air fans and the flap positions of the flaps assigned to the supply air ducts as a function of the control parameters, whereby proportionate assignment of the supply air volume from each supply air duct to the corresponding room zone is derived.
 28. The method as recited in claim 27, wherein at least one of a recirculating air portion and fresh air portion is controlled as a function of the control parameters.
 29. The method as recited in claim 28, wherein the control of the at least one of the recirculating air portion and the fresh air portion is carried out according to physical characteristic values as a function of the control parameters. 